Extracted stay points:
laltitude	longitude	arriving time	leaving time
39.93749174242428 116.38987749090921 2009-04-05,08:24:58 2009-04-05,09:24:18
39.94441436585365 116.37560874796743 2009-04-05,10:05:33 2009-04-05,11:26:18
